Can somebody please explain to me what and how the 'Use Mask' feature in the Full Precision Blur' Image Filter is supposed to work? I usually use FP Blur on the object(s) that I want and rendert them out and then comp those into the final render later if I do not want everything blurred. From the manual it sounds like I could use the mask feature in pre-render mode to select what I want blurred and leave the rest un-blurred but have never to get it to work.
Any clues?

uncommongrafx

06 June 2003, 04:08 PM

Go here for a start:
Old post (http://www.cgtalk.com/showthread.php?s=&threadid=22923&perpage=15&highlight=precision%20blur&pagenumber=2)

Chewey was great in sharing this insight.

aurora

06 June 2003, 01:44 PM

uncommongrafx, Thanks for the reply. I saw that one and another thread from leigh on special buffers when I did a search for info on FP-blur. Unfortuneatly if I try what eugeny does in that thread I still get the same results; a blur on everything. What my impression is , is that I could apply a pre-render mask on a given object in a scene and only it would take on the FP-blur filter and the rest of the oimage would stay crystal clear. Does anybody know if I'm wrong on this assumption?

On a side note did leigh ever create a tut on special buffers?

uncommongrafx

06 June 2003, 01:47 PM

I think, no, you can't do what you want in the program.

However, you might try to reverse what he did, i.e., try to type negative numbers in or the way it's set up.

You have me wondering....

Off to try!

uncommongrafx

06 June 2003, 01:58 PM

Following Chewey's tute I just used Invert Mask and was able to have selective blurring.

You can do what you want, it would seem.

aurora

06 June 2003, 02:03 PM

Invert Mask! I did not try that. I'll give it a spin in a couple of minutes. Heres hoping. Thanks again!

leigh

06 June 2003, 02:19 PM

Originally posted by aurora
On a side note did leigh ever create a tut on special buffers?

Yes, I did write a whole load about it, but before I put it online, I got my book contract, and decided to keep it for my book.
However, here is how to use Special Buffers with FP Blur...

The Full Precision Blur effect can be controlled by Special Buffers simply to determine which surfaces it blurs. This is a pretty straightforward one to use.

To use it, open up its panel by double clicking on it in the Image Filters list in the Effects panel. For ease of use in this case, make sure that it is the FIRST filter in the list. Okay, now that you have the FP BLur panel open, select Special Surface as the Mask option. If you do not do this, you will blur everything in the scene.

Now, set up the blur as you want it to be.

Then go to your Surface Editor and select the surface that you want blurred. If you want an entire object blurred, either assign a single surface to the entire object, or make sure that every surface on the object has Special Buffers set up on it, because Special Buffers works with surfaces only, not objects.

Okay, not go to the Advanced tab in the Surface Editor and click on Special Buffers to open the panel. In the first field, enter in the value for the blur that you want. The reason you do it in the first field is because the FP Blur is the first filter in the Effects panel filters list (that is why I said to keep it at the top, for simplicity in this example).
There are only 4 filters that work with Special Buffers, and this list in the Buffers panel corrosponds directly to the order they appear in the Effects panel filters list. So if, for example, the FP Blur was second in the list there, you would assign it's Special Buffers value in the second field of the Buffers panel list.

Got it? Cool...

Now, each of the filters works a little differently in the Special Buffers panel. The way in which I find that FP Blur works best is to take the value that you had in the actual FP BLur panel and multiply it by 10, and enter that value in the Special Buffers panel.

So if, for example, you have 7 blur in the FP Blur panel, you can enter in a value of 70 in the Special Buffers panel.

I hope this all makes sense! :D

aurora

06 June 2003, 02:41 PM

OK, now I'm confused. First, thanks leigh for responding.
I was just trying a very simple scene which included a box with a sphere in front of it. Applied the FP Blur image filter. Selected either Invert or pre-render for the masking and set the special buffers accrodingly and it worked perfect. Then I went into the scene that I wanted to apply the masked FP Blur to and it still does not work on it. Guess I'll have to play some more and figure out what is going on. FWIW, I only have FP Blur using special buffers right now so its not a conflict of intrest with say the corona filter.

aurora

06 June 2003, 02:44 PM

Oh hey leigh, thanks for the tip on the 10x special buffer setting. I just played with that on my simple scene I created above and it seems to be a pretty magic formula for pleasing results!

uncommongrafx

06 June 2003, 02:53 PM

What's your scene consist of? I'm curious now that I'm here. ;)

Thanks for letting us assist.

leigh

06 June 2003, 02:57 PM

Then I went into the scene that I wanted to apply the masked FP Blur to and it still does not work on it.

Hmmm... perhaps what you should do is clear anything you set up already in that scene (the filter and any Special Buffer settings), and redo it from scratch again. Sometimes that helps... you might have accidently selected an option somewhere that is causing the problem.

Oh hey leigh, thanks for the tip on the 10x special buffer setting. I just played with that on my simple scene I created above and it seems to be a pretty magic formula for pleasing results!

Hehe, great to hear ;)

aurora

06 June 2003, 07:38 PM

uncommongrafx, its basically a pretty simple animated logo for a client. Its composed of 2 layers of a background object for a total of 6 surfaces. 2 rows of text for another 6 surfaces. A third object which is rather hard to explain but has a very convoluted geometry 4 surfaces but extremely complexe textures (2 weeks of playing to get it right), this is the object that I want the FP-Blur on but nothing else. Several lights including a 1 volumetric light, 1 light for a lens flare. And a one null with a particle emitter and a light attached (a simple meteor effect). When I did this originally I set it up, rendered in layers and composited it all together later in AE. Although it would take MUCH longer to render, I would like to see what would happen if I could apply the FP Blur to the one object but nothing else thus allowing the light to help illum the rest of the scene. Just curious more then anything else. Sorry I'm not more specific but the client does not me showing anything from it yet since they have not started using it as of yet. What ever.
I think I'm going to try what leigh suggested and take the pieces and put it all back together again and see what happens.

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